In recent years, with increased and diversified information required by a driver for driving, head-up display devices (hereinafter also referred to as “HUD (head up display) devices”) that display a virtual image of information to be notified the driver of such as information high in the degree of urgency on the window shield of the vehicle, and allow the virtual image and the foreground of the vehicle to be visually recognized in the superimposed manner have been employed for driver seats of the vehicles such as automobiles or trains.
The HUD device of this type arranges the display source inside of a dashboard of the vehicle, reflects the display light indicative of the display information such as images or characters displayed by the display source toward the projection area provided in the window shield by the reflector such as a magnifying mirror, displays the virtual image of the display information on the projection area, and allows the virtual image and the foreground of the vehicle to be visually recognized in the superimposed manner (for example, refer to Patent Literature 1).
Incidentally, drivers are different in eye level due to individual differences such as seating heights. For that reason, in the HUD device where a range (hereinafter referred to as “eye range”) of an eye position at which the virtual image of the display information displayed on the projection area can be viewed is limited, unless the display light forming the virtual image of the display information faces the driver's eyes, the driver cannot sufficiently visually recognize the superimposed display information. For that reason, there is disclosed the HUD device in which an adjustment unit is provided for adjusting an installation angle (that is, posture) of the reflector, and the driver per se adjusts the adjustment unit so that the display light faces the driver's eyes according to the adjustment.
As illustrated in FIG. 23, an HUD device 701 of this type includes a box-shaped case 710 having an opening 719, a display source 720 disposed within the case 710, a reflector 730 rotatably disposed within the case 710, and a driver 740 functioning as the adjustment unit for rotating the reflector 730.
The case 710 is disposed inside of a dashboard 780 of the vehicle. The opening 719 of the case 710 coincides with an opening 782 formed in an upper surface 781 of the dashboard 780. Also, an opening bezel 783 of a square frame shape is disposed along an edge of the opening 782. The opening bezel 783 emits a light, and the light is so projected as to coincide with an outer edge of a projection area 771 of a window shield 770 to display a virtual image 783V thereof. The reflector 730 is configured by, for example, a magnifying mirror, and reflects the display light of the display information displayed on the display source 720 toward the projection area 771 disposed in the window shield 770 of the vehicle through the opening 719 of the case 710. With this configuration, a virtual image 720V of the display information is displayed on the projection area 771. The driver 740 includes, for example, a motor and a gear mechanism. The driver 740 rotates the reflector 730 so as to move a projection position (that is, position of virtual image 720V of display information) of the display light on the projection area 771 in a vertical direction of the vehicle on the basis of a control signal transmitted from a controller not shown by operating an operation switch not shown disposed on the dashboard 780 through the driver. Thus, the driver 740 adjusts the installation angle.
The HUD device 701 projects the display light of the display information on the display source 720 to the projection area 771, and displays the virtual image 720V of the display information inside of the virtual image 783V of the opening bezel 783 (FIG. 24(a)). Also, as illustrated in FIG. 23, the HUD device 701 adjusts the installation angle of the reflector 730 according to an eye position EPC of a driver with a standard seating height, an eye position EPH of a driver with a high seating height, or an eye position EPL of a driver with a low seating height. Then, the HUD device 701 displays the virtual image 720V of the display information at a position (720VC) visually recognizable by the driver with the standard seating height, a position (720VH) visually recognizable by the driver with the high seating height, or a position (720VL) visually recognizable by the driver with the low seating height.
According to the HUD device 701 of this type, even when the driver different in the level of the eye position such as the driver with the standard seating height, the driver with the high seating height, or the driver with the low seating height gets on the vehicle, the installation angle is adjusted by rotating the reflector 730. As a result, the projection position of the display light travels in the vertical direction so that the display light is directed at the eye of each driver (that is, the above-mentioned eye range). This makes it possible to adjust the virtual image 720V of the display information to a visually recognizable position.